JPH0942995A - Phase error correction method for two periodic signals and phase error correction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate to form a device, and lessen the dispersion of precision resulting from individuals who adjust the device by obtaining the difference between the amplitude of first intersection of two signals of same cycle having a phase difference and the amplitude of second intersection when the same signals have a desirable phase difference. SOLUTION: Two periodic signals 3a, 3b are generated by a signal generator 1, being kept each converted into electric signals by an electric circuit 2, and sent to a digital signal processing means 5 signal amplitude equal by variable amplifiers 12a, 12b. The amplitude of first intersection where the signals 3a, 3b cross mutually is detected by the processing means 5, and the difference between the detected amplitude of the intersection and the amplitude of second intersection when respective signals have a desirable phase difference is obtained. A phase error, which is a deviation amount from phases when respective phases are in a desirable state, is obtained from the obtained amplitude difference. A correction factor, by which the phase difference of the signals 3a, 3b are corrected to a desirable phase difference, is obtained from the phase error, and a phase correction is conducted on the signals 3a, 3b having equal cycles using the correction factor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phase error correction device for correcting a phase difference to a desired value in a signal generator such as an encoder which generates two periodic signals having a phase difference according to the movement of a position or an angle. It is about.

[0002]

2. Description of the Related Art Conventionally, correction of two periodic signals having a phase difference is performed in an analog manner. This correction, for example,
The phase difference is adjusted by adjusting the Lissajous waveforms of the two periodic signals so as to form a perfect circle.

FIG. 7 is a diagram showing the structure of a conventional phase correction device.

In FIG. 7, reference numeral 701 denotes a signal generating means for generating two periodic signals according to changes in position or angle, and 702.
Is an electric circuit for converting the two periodic signals generated by the signal generating means 701 into an electric signal whose phase difference is adjusted,
702a is a volume for adjusting the resistance value on the electric circuit 702 to correct the phase difference, 703a and 703b are two periodic signals converted into electric signals, and 720 is the two periodic signals 703a and 703b. Measuring device for displaying the waveforms (hereinafter Lissajous) taken on the axis and the horizontal axis, 7
21 is a Lissajous displayed by the measuring device 720.

Conventionally, signal correction of an encoder that outputs an analog resolver two-phase signal has been performed by adjusting a resistance value on an electric circuit 702 that converts the signal of the encoder into an electric signal at the time of shipment.

First, the amplitude and offset are corrected by a volume not shown. Normally, the phase is adjusted after setting the same amplitude and zero offset. The method of correcting the phase will be described below.

The phase difference between the periodic signals of the above encoder is 9
Since 0 degree is a normal value, it is known that a circle is drawn when each of the two periodic signals is displayed on the vertical axis and the horizontal axis.

The electric circuit 702 corrects the amplitude and offset of the two periodic signals output from the signal generating means 701 and outputs them as signals 703a and 703b. Each of the signals 703a and 703b is input to the measuring device 720, and the Lissajous 721 is drawn. Signals 703a, 70
The relationship between 3b and Lissajous 721 is shown in FIG.

FIG. 8A shows the signal 7 when the phase error is 5 degrees.
03a, 703b and Lissajous 721. The shape extends to the upper right and lower left. FIG. 8B is a Lissajous when the phase error is −5 degrees, and has a relationship opposite to that of FIG. 8A.

When making the adjustment, while observing the Lissajous 721 displayed as described above, the volume 702a
Are adjusted so that the Lissajous 721 becomes a perfect circle as shown in FIG. At this time, the phase difference between the two periodic signals becomes 90 degrees, which means that the two signals are properly adjusted.
Conventionally, the phase has been corrected in this way.

As a signal processing device for detecting an angle based on the signal whose phase has been corrected as described above, there are those shown in FIGS. 9 and 10.

FIG. 9 is a block diagram showing an example of the configuration of a signal processing circuit conventionally used in a rotary encoder (hereinafter referred to as "encoder").

The figure shows a block diagram of the interpolation circuit. In the figure, 90 _A and 90 _B are frequency multipliers, which double the frequencies of the input signals A and B, respectively, and output them. Reference numeral 92 is a phase detector, which is a frequency multiplier 90 _A , 9
The two sine wave signals A and B multiplied by 0 _B are taken in, and the phase, which is the information affecting the position or angle, is detected from both. Reference numeral 93 is an integrator, which integrates the phase signals from the phase detector 92 and outputs a cumulative angle θ.

In the above signal processing circuit, the two input signals A and B output from the encoder are sine wave signals having a phase difference of 90 ° from each other according to the rotation angle of the encoder. These input signals A and B output p ₀ sine wave pulses when the rotary shaft of the encoder makes one rotation.
The input signals A and B are converted by the frequency multipliers 90 _A and 90 _B into signals having a doubled frequency (2p ₀ per one rotation of the rotary shaft) and output to the phase detector 92.

The phase detector 92 detects the phases of the two input signals that have been input with a predetermined accuracy, for example, an accuracy of 1/40 cycle, converts it into a digital signal, and outputs it to the integrator 93 in the next stage. The integrator 93 cumulatively counts the input digital signal as the number of pulses, obtains the cumulative rotation angle θ from the cumulative count number n by the following equation, and outputs it.

Θ = 360 ° · n / (2 · 40 · p ₀ ) In this case, finally, the number of output pulses per rotation of the rotary shaft of the encoder is 80 times the signal output by the encoder,
That is, it becomes 80 · p ₀ .

However, the above-mentioned method has a problem that the circuit scale becomes large, and another method has been devised.
FIG. 10 is a block diagram of a signal processing circuit adopting the above method. In the figure, 91 _A and 91 _B are A / D converters, which convert the analog signals A and B into digital signals A _D and B _D. Reference numeral 97 is an arithmetic unit (CPU) such as a DSP or a microcomputer.

In FIG. 10, two input signals A and B output from the encoder are A / D converters 91 _A ,
91 _B converts into digital signals A _D and B _D ,
It is input to the CPU 97. And arithmetic unit (CPU) 9
Reference numeral 7 obtains and outputs the phase δ within one cycle of the input signals A and B by the following equation using the digital signals A _D and B _D.

Δ = tan ^-1 (B _D / A _D ) On the other hand, the input signals A and B are input to the frequency multipliers 90 _A and 90 _B , and the output multiplied by the m-fold frequency is the phase detector. 9
2 is input. The phase detector 92 sets the phase of the input signal to 1
It is detected with a precision of / t cycle, converted into a digital signal, and output to the integrator 93. The integrator 93 counts the human power digital signal to obtain the cumulative count number n, and p = n / (m · t), where p is an integer and outputs the cumulative pulse number p of the input signals A and B, and within one cycle. And the cumulative rotation angle θ are calculated by the following equation and output.

Θ = 360 ° · {p + (δ / 2π)} / p ₀ According to the above method, the phase δ of the input signal can be accurately detected with a relatively small-scale circuit configuration. Since the phase δ is obtained by calculation from the digital signals A _D and B _D obtained by A / D converting the input signal from, the calculation accuracy is determined by the accuracy of the A / D converters 91 _A and 91 _B. Therefore, the input signals A _A and B _{A to the} A / D converter are
Has the peaks of its signal, and it is A /
It is desirable in terms of accuracy to be as large as possible within the range of the D converter.

However, since the amplitudes of the input signals A and B actually output from the encoder fluctuate under the influence of the rotational accuracy of the slit plate of the encoder, etc., A /
During D conversion, the level must be adjusted so that the peak value of the input signal falls within a certain value. Therefore, when the input signal has amplitude fluctuations, the input peak value to the A / D converter becomes small in a certain part of the input signal and the A / D conversion accuracy decreases, which deteriorates the phase detection accuracy as a whole. It may happen.

In order to solve the above problems, the displacement amount of the object is detected by using two sinusoidal input signals having a predetermined phase difference, which are output according to the displacement of the object. In the displacement amount detecting device, an amplification means capable of arbitrarily setting an amplification gain of the input signal, an A / D conversion means for converting the amplified input signal into a digital signal,
Calculating means for calculating the phase of the input signal from a predetermined relational expression from the two input signals converted into digital signals; waveform storing means for storing the input signal over a predetermined displacement range of the object; Gain setting means for setting the amplification gain of the amplifying means is provided, and when the input signal is converted into a digital signal when the displacement amount is detected, the predetermined displacement range is divided into a plurality of parts, and the divided parts are divided into a plurality of parts. There has been proposed a displacement amount detecting device provided with adjusting means for adjusting the amplification gain of the amplifying means so that the peak levels when the maximum input peak signal is converted into a digital signal are made uniform.

[0023]

In the above-described conventional phase correction method, since the human visually adjusts the Lissajous figure, it is unavoidable that individual differences occur. Also,
Even if a skilled worker performs it, an error of about ± 1 degree will inevitably remain, and it is very difficult to adjust it below that. Also in the displacement amount detecting device described with reference to FIGS. 9 and 10, the gain adjustment of the amplifying means is only automated, and the output itself of the signal generating device is not corrected.

In addition, a measuring instrument for displaying a signal is required for the adjustment, and when re-correction is required due to the passage of time or the like, the encoder is installed from a state in use to a dedicated jig. It took a lot of work such as reworking, and it was not easy to use.

In order to solve the above problems, the present invention automates the phase correction procedure.

For automation, the two periodic signals are digitized by analog-digital conversion, and the processing procedure automated by the digital signal processing means is executed.

However, the detector itself is a physical quantity such as light or magnetic field, and an analog electric circuit portion is always left in order to convert these into electric signals. Further, an analog electric circuit is necessary to adjust the amplitude to a level applicable to digital conversion.

Therefore, the present invention does not deny the adjustment function included in the electric circuit as described above, but complements the accuracy that cannot be adjusted by the conventional method, and is inevitably included by the conventional method. The correction of the present invention is intended to absorb individual differences.

The phase error correction method for two periodic signals of the present invention for achieving the above object detects the amplitude of a first intersection point at which two signals having the same period having a phase difference intersect each other, and the detection is performed. The difference between the amplitude of the intersecting point and the amplitude of the second intersecting point when each signal has a desired phase difference is obtained, and each signal is in a desirable state from the difference in amplitude between the first intersecting point and the second intersecting point. Then, a phase error, which is the amount of deviation from the phase, is obtained, and a correction coefficient, which is a coefficient for correcting the phase difference of each signal to a desired phase difference, is obtained from the phase error. It is characterized in that the phase is corrected using a coefficient.

In this case, the amplitude of the first intersection may be detected when the absolute value of the difference between the two periodic signals is smaller than a predetermined range.

Further, the amplitude of the first intersection may be detected at the point where the absolute value of the difference between the two periodic signals becomes the minimum.

In any of the above cases, the phase error is obtained from the difference between the amplitudes of the first intersection and the second intersection, and the periodic signal is obtained in the vicinity of the intersection when the phase difference between the signals is in a desired state. It may be performed by linearizing and obtaining by algebraic calculation.

Further, the phase error may be obtained from the amplitude difference at the intersection by referring to the table of the inverse trigonometric function near the intersection when the phase difference between the signals is in a desired state.

Furthermore, obtaining the phase error from the difference in the amplitude of the intersection may be obtained by calculating the inverse trigonometric function.

According to another aspect of the present invention, there is provided a method for correcting a phase error between two periodic signals, wherein one of two signals having a certain phase difference and having the same period is used as a reference signal, and the reference signal has a certain phase. And measure the amplitude of the other signal,
Obtaining a phase error that is the amount of phase shift from the phase when each signal is in the desired state from the amplitude, and obtaining a correction coefficient for correcting the phase difference of each signal to the desired phase difference from the phase error, It is characterized in that two signals having the same period are phase-corrected by using the correction coefficient. In any of the above inventions, the phase error detection, the correction coefficient derivation, and the phase correction may be performed after the amplitudes of the two periodic signals are made equal.

Further, the correction coefficient may be obtained by an approximate calculation based on the phase error, and the approximate calculation may be a finite number of recursive iterative calculations.

The correction coefficient may be obtained by referring to the table of the relationship between the phase error and the correction coefficient.

The correction coefficient may be obtained by calculating a trigonometric function based on the phase error.

Further, the calculation of the phase correction using the values of the two periodic signals and the correction coefficient may be obtained by algebraic calculation.

The phase error correction device for two periodic signals of the present invention comprises an analog-digital conversion means for digitizing two signals having the same period and having a phase difference, and the two signals having the same period in phase. And a digital signal processing means for performing correction, and the digital signal processing means performs the phase correction by any one of the methods described above.

In this case, the digital signal processing means has a storage unit that does not lose the stored value regardless of whether the power is turned on or off, and the digital signal processing unit stores the correction coefficient in the device and stores the previous correction value when the power is turned on. You may use and correct it.

In the present invention configured as described above, the phase is corrected only by numerical calculation without using visual observation as in the prior art, so that the device can be easily made and it may depend on individual differences when adjusting the device. Less variation in accuracy.

[0043]

Next, the present invention will be described with reference to the drawings.

As an apparatus for correcting the phase difference between two periodic signals having a phase difference to a desired value as in the present invention,
Since the configuration for digitally converting and processing by the digital signal processing means and the method for correcting the amplitude have already been proposed as described above, here, the correction of the phase difference will be described on the assumption that the amplitudes of the two periodic signals are equal. To do.

Example 1 FIG. 1 is a diagram showing the configuration of a first example of the present invention, and the method of approximation calculation used in this example will be described below.

In FIG. 1, 1 is a signal generator that generates two periodic signals in response to changes in position or angle, 2 is an electric circuit that converts the signal of the signal generator 1 into an electric signal, and 12a, 1a.
Reference numeral 2b is a variable amplifier for keeping the amplitude of the output signal of the electric circuit 2 equal, and has a variable amplification factor. Four
a and 4b are A / D converters (analog-digital conversion means), 3a and 3b are electric signals, and second and first periodic signals converted into digital signals, and 5 are digital signal processing means, The amplification factors of the variable amplifiers 12a and 12b are determined.

The digital signal processing means 5 determines the amplification factors of the variable amplifiers 12a and 12b from the maximum value and the minimum value of the periodic signal 3 so as to obtain an appropriate amplification factor, whereby the amplitudes of the two periodic signals are kept equal. Is dripping

FIG. 2 is a diagram for explaining the phase relationship between the two periodic signals 3a and 3b. As mentioned above, the variable amplifier 12 is used.
The amplitude of each periodic signal is the same because it is adjusted by.

Of the periodic signals shown in FIG. 2, the first periodic signal 3b is the reference of the two periodic signals, and 3a-1 is the second periodic signal when there is no phase error. Therefore, the phase difference from the first periodic signal 3b is 90 degrees. 3
a-2 is the second periodic signal when the phase error is δ, 6 is the intersection when there is no phase error, and when normalized, that is, when the maximum amplitude value is 1.0, the sine or cosine at 45 degrees Value (this value is referred to as DEG45). 7
CROSS this amplitude at the intersection when there is a phase error δ
Let's call it AB.

FIG. 3 is a flow chart showing the first method for finding the intersection. First to find CROSSAB
The method will be described with reference to FIG. It should be noted that these processes are carried out by the digital signal processing means 5 based on the value converted into the digital signal by the analog-to-digital conversion means at regular sampling intervals.

When the intersection detection mode is started, the digital conversion value of the periodic signal 3 is obtained for each sampling (step S1). Next, the difference between the absolute value of the difference between the values of the two periodic signals and the predetermined threshold value ERR is compared (step S2). When the absolute value of the difference is larger than the threshold value ERR, it is determined that the intersection is not reached and nothing is performed to determine the end (step S4). When the absolute value of the difference is smaller than the threshold value ERR, the absolute value of the value of A or B is set to the intersection value CRO.
It is set to SSAB (step S3), and the end determination is performed (step S4). The above operation is repeated until exiting the intersection detection mode, and CROSSA when exiting the intersection detection mode
Let the value of B be the value of the intersection.

In the intersection point detection mode, the phase is not corrected. That is, the phase error is set to 0.

FIG. 4 is a flow chart showing a second method for finding CROSSAB. A second method for obtaining CROSSAB will be described with reference to FIG.

In the intersection detection mode, ERRMIN
Is set to a sufficiently large value (step S5), and a digital conversion value of the periodic signal is obtained for each sampling (step S5).
6). Next, the absolute value of the difference between the values of the two periodic signals is compared with ERRMIN set in step S5 (step S7). When the absolute value of the difference is larger than ERRMIN, it is determined that the intersection is not reached and nothing is performed to determine the end (step S9). When the absolute value of the difference is smaller than ERRMIN, the absolute value of the difference at this time is set as a new ERRMIN value, the value of A or B is set as CROSSAB (step S8), and the end determination is made (step S9). The above operation is repeated until the intersection detection mode is exited, and the value of CROSSAB when exiting the intersection detection mode is taken as the intersection value.

Next, the phase error δ is calculated from the difference between the intersection points 6 and 7.
A method for obtaining the following will be described.

FIG. 5 is a diagram for explaining a method of obtaining the phase error δ from the amplitude value CROSSAB at the intersection.

The periodic signals 3a-1, 3a-2 and 3b are set to 45
The straight lines when linearly approximated by the differential coefficient in degrees are 9a, 9b, and 10a, respectively. The value at intersection 7 is CROSS
Assuming AB, the half length of the base of the triangle surrounded by the straight lines 9a, 9b, 10a can be calculated by δ / 2 = (CROSSAB-DBG45) ÷ DBG45 (1).

If the line parallel to the straight line 10a and passing through the intersection of the horizontal axis 11 and the straight line 9b is 10b, then the horizontal axis 11 and the straight line 10
b, the triangle enclosed by the straight line 9b and the triangle enclosed by the straight lines 9a, 9b, 10a are the same, so the length of the base, that is, the phase error δ, is obtained by doubling the value obtained by the equation (1). You can

Next, the periodic signal 3a-2 having the phase error δ
A method of obtaining the periodic signal 3a-1 having no phase error from will be described. 3b is A = cos θ, 3a-1 is B = sin
Let θ and 3a−2 be B ′ = sin (θ + δ).

To correct the phase is to make the measured value B ′ including the phase error δ into B having no phase error. From the trigonometric formula, B'can be decomposed as follows.

B ′ = sin (θ + δ) = sin θcosδ + cos θsinδ = Bcosδ + ASinδ (2) Therefore, B is obtained from the measured values A, B ′ and δ.
It can be obtained from the following equation using inδ and cosδ.

B = (B′−A · sin δ) ÷ cos δ (3) Therefore, the coefficients sin δ and cos δ are used for correction.
The value of must be calculated.

Next, correction coefficients sin δ and cos δ are calculated from δ.
The method of obtaining

Since sin δ is approximately equal to δ when δ is near 0, sin δ is approximated by δ.

From the relationship of sin ² δ + cos ² δ = 1, cos δ can be calculated by substituting sin δ≅δ and calculating cos δ = (1-δ ² ) ^1/2 (4). The calculation of the square root is performed by a function in digital signal processing, or α = 1-δ ^{2 is set,} and the solution X of x ² −α = 0 is obtained by repeating the approximation calculation of the Newton method. The number of iterations is generally determined by stopping the convergence, but if the existence of the solution and the convergence are known so as to find the value of the square root, and you want to end the calculation during the sampling period, repeat the calculation beforehand. It is also possible to decide the number of times of, and terminate the approximation calculation after calculating the number of times.

The obtained solution X is an approximate value of cos δ.

Sin δ and cos obtained as described above
The approximate value of δ is substituted into sin δ and cos δ in equation (3) to correct the phase. Since the approximate values of the correction coefficients sin δ and cos δ are constant after the correction error δ is obtained, they can be sufficiently calculated during sampling.

If the correction coefficient is stored (saved) in a battery-backed memory or a non-volatile memory, the value will not be lost even if the power is turned off, and the correction coefficient can be corrected by the previous correction coefficient when the power is turned on. You can It should be noted that the correction may be made only when necessary, such as when the encoder is replaced or when a change with time occurs.

Second Embodiment: Table Reference Method A second embodiment of the present invention will be described.

The structure of this embodiment and the two methods of obtaining the intersection are the same as those of the first embodiment, and only the method of obtaining the phase error δ is different from that of the first embodiment. This will be described with reference to FIG.

The periodic signals when there is no phase error intersect at 45 degrees, and the phase at this time is π / 4 radians. The phase of the intersection at the phase error δ is θc.

In order to obtain the phase θc of the intersection, the inverse trigonometric function of cosine is required. Therefore, the digital signal processing means 5 (see FIG. 1) stores a first table indicating the inverse trigonometric function of the cosine around 45 degrees as shown in FIG. 6A. The first table shown in FIG. 6A shows a case in which a range of ± 5 degrees centering on 45 degrees is covered. Intersection CR
Referring to Table 1 using the value of OSSAB as an index,
The phase θc of the intersection can be obtained. The phase error δ is obtained from the following equation.

Δ = (θc−π / 4) × 2 (5) Next, a method of obtaining the correction coefficient from the phase error δ will be described.

6B and 6C are a second table and a third table showing the relationship between sine and cosine around 0 degree, respectively, which are stored in the digital signal processing means 5. The figure shows the case of covering the range up to ± 5 degrees. From the table using the phase error δ as an index, sin
The values of δ and cos δ can be obtained.

Regarding the structure of each table described above, the symmetry of sin and cos with respect to 0 degree (sin has the same absolute value and different sign, cos has the same value regardless of the sign of δ) is used. You can also halve the capacity of the table.

The values written in the above tables are substituted into the equation (3) to correct the phase. The correction coefficient can be stored in the same manner as in the first embodiment.

Example 3: A trigonometric function is calculated.

In the above two embodiments, the case where the trigonometric function calculation and the inverse trigonometric function calculation cannot be directly performed has been described.
If we can compute trigonometric and inverse trigonometric functions, we can do simpler. The case will be described.

The method of obtaining the intersection is the same as in the first embodiment. If the inverse trigonometric function can be calculated, the phase of the intersection can be calculated as θc = cos ^-1 (CROSSAB) (6), and the difference between this value and 45 degrees (π / 4) is half the phase difference obtained. Since this is equivalent, the phase error δ can be obtained by substituting it in the equation (5). Corrected counts are also sin δ and c
Since osδ can be calculated, it can be obtained.

Therefore, the phase can be corrected by applying the values of sin δ and cos δ to the equation (3). The correction coefficient can be stored in the same manner as in the first embodiment.

In the first embodiment, a method for obtaining both the phase error detection and the correction coefficient by approximate calculation will be described, in the second embodiment, a method for obtaining both by a table reference will be described, and in the third embodiment, both will be obtained by a function. However, it is of course possible to detect the phase error by referring to a table and obtain the correction coefficient by an approximate calculation, or to realize it by arbitrarily combining.

Embodiment 4 In each of the above embodiments, when the phase error δ is obtained from the intersection of two periodic signals when the phase error δ is obtained from the amplitude value of the other signal when the reference signal has a certain phase However, in this embodiment, a method of obtaining the phase error δ from the amplitude of the other one in a certain phase with reference to one periodic signal will be described.

This embodiment will be described with reference to FIG. The first periodic signal 3b is used as a reference signal. As an example, a method of measuring the amplitude of the second periodic signal 3a when the amplitude of the first periodic signal 3b which is the reference signal becomes 1 will be described. The value of the second periodic signal 3a when the phase error is 0 is 0 as indicated by 3a-1. As indicated by 3a-2, when there is a phase error, the value of the amplitude becomes a point indicated by 13 (the amplitude at this time is CROSSZ). This CROS
There are three methods for obtaining the phase error δ from SZ as described in the first to third embodiments.

Method 1: In the approximation by the linearization, the value of CROSSZ at the time of the phase error δ is sin δ. Therefore, s is the inverse approximation to the case explained in the derivation of the correction coefficient of the first embodiment.
Let the value of in δ be an approximate value of δ. That is, CROSS
The value of Z is an approximate value of the phase error δ.

Method 2: A table has an inverse trigonometric function of sine around 0 degree, and the value of δ is obtained by referring to the table with CROSSZ as an index. The table is similar to the table 1 in FIG. 6A, and the table 1 is centered at 45 degrees, whereas the table 1 is centered at 0 degrees. ± 5 in Fig. 6 (d)
4 shows a fourth table of degree ranges.

Method 3: The inverse trigonometric function is calculated and the phase error δ is calculated by the following equation.

Δ = sin ⁻¹ (CROSSZ) (7) If the phase error δ is obtained by any of the above three means, the correction coefficient is derived by the method described in the first to third embodiments, Phase correction calculations can be performed. The correction coefficient can be stored in the same manner as in the first embodiment.

[0088]

Since the present invention is configured as described above, it has the following effects.

1. Since the correction of the phase is performed only by a predetermined numerical calculation, there is an effect that the device can be easily made and the variation of the accuracy due to the individual difference in adjusting the accuracy of the completed device can be reduced.

2. Even a minute difference can be detected and can be corrected with high accuracy.

3. Since it can be implemented in the signal processing means of the periodic signal, it is possible to make corrections in the state of actual use without removing the instrument from its use or attaching a measuring instrument.

[0092] 4. Since the correction coefficient can be saved, it is possible to save the trouble of having to make correction every time the power is turned on.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an exemplary embodiment of the present invention.

FIG. 2 is a diagram showing a phase relationship between two periodic signals.

FIG. 3 is a diagram illustrating a first flowchart.

FIG. 4 is a diagram illustrating a second flowchart.

FIG. 5 is a diagram illustrating a method of obtaining a phase error from the amplitude of an intersection.

FIG. 6 is a diagram illustrating a table.

FIG. 7 is a diagram showing a configuration of a conventional example.

FIG. 8 is a diagram illustrating a conventional adjustment method.

FIG. 9 is a diagram showing a configuration of an amplification factor adjusting means that has been conventionally used.

FIG. 10 is a diagram showing a configuration of a conventional amplification factor adjusting means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 signal generator 2 electric circuit 3a 2nd periodic signal 3b, 3b-1, 3b-2 1st periodic signal 4a, 4b analog-digital conversion means 5 digital signal processing means 6, 7 intersection 9 linearization of the periodic signal Straight line 10 Straight line obtained by linearizing a periodic signal 11 Lines of zero amplitude 12a, 12b Variable amplifier 13 Detection points when there is a phase error S1 to S9 steps

Claims (14)

[Claims] 1. The amplitude of a first intersection at which two signals having the same period having a phase difference intersect each other is detected, and the amplitude of the detected intersection and the second intersection when each signal has a desired phase difference. A difference with the amplitude is obtained, a phase error that is a deviation amount from the phase when each signal is in a desirable state is obtained from the difference in the amplitude between the first intersection and the second intersection, and each signal is obtained from the phase error. Of the phase difference between the two periodic signals, wherein a correction coefficient that is a coefficient for correcting the phase difference of 1 to a desired phase difference is obtained, and the two signals having the same cycle are phase-corrected using the correction coefficient. Method. 2. The phase error correction method for two periodic signals according to claim 1, wherein the amplitude of the first intersection is detected when the absolute value of the difference between the two periodic signals is smaller than a predetermined range. A phase error correction method for two periodic signals, characterized in that 3. The phase error correction method for two periodic signals according to claim 1, wherein the amplitude of the first intersection is detected when the absolute value of the difference between the two periodic signals is minimum. A method for correcting the phase error between two periodic signals. 4. The phase error correction method for two periodic signals according to claim 1, wherein the phase error is calculated from the difference in amplitude between the first intersection and the second intersection. A method for correcting a phase error between two periodic signals, which is characterized by linearizing the periodic signal in the vicinity of an intersection when the phase difference between the respective signals is in a desirable state, and by performing algebraic calculation. 5. The phase error correction method for two periodic signals according to claim 1, wherein the phase error is determined from the difference in amplitude of the intersections, and the phase difference between the respective signals is desirable. The method for correcting the phase error of two periodic signals is performed by referring to the table of the inverse trigonometric function in the vicinity of the intersection at time. 6. The phase error correction method for two periodic signals according to claim 1, wherein the phase error is obtained from the difference in amplitude of the intersections by calculating an inverse trigonometric function. A method for correcting a phase error between two periodic signals, characterized by: 7. One of two signals having a certain phase difference and having the same period is used as a reference signal, the amplitude of the other signal is measured when the reference signal has a certain phase, and each signal is desirable from the amplitude. Obtain the phase error that is the amount of phase shift from the phase when in the state, obtain the correction coefficient for correcting the phase difference of each signal to the desired phase difference from the phase error, two signals with the same period A phase error correction method for two periodic signals, characterized in that phase correction is performed using the correction coefficient. 8. The phase error correction method for two periodic signals according to claim 1, wherein the phase error is detected, the correction coefficient is derived, and the phase correction is performed by using the amplitudes of the two periodic signals. A method for correcting a phase error of two periodic signals, which is performed after equalization. 9. The phase error correction method for two periodic signals according to claim 1, wherein the correction coefficient is obtained by approximation calculation based on the phase error, and the approximation calculation is recursion. A method for correcting a phase error of two periodic signals, which is characterized by repeating the iterative calculation of equations a finite number of times. 10. The method for correcting a phase error of two periodic signals according to claim 1, wherein the correction coefficient is obtained by referring to a table of the relationship between the phase error and the correction coefficient. A characteristic method for correcting a phase error between two periodic signals. 11. The phase error correction method for two periodic signals according to any one of claims 1 to 7, wherein the correction coefficient is obtained by calculation of a trigonometric function based on the phase error. Method for phase error correction of two periodic signals. 12. The method for correcting a phase error of two periodic signals according to claim 1, wherein the calculation of the phase correction using the values of the two periodic signals and the correction coefficient is an algebraic calculation. A method for correcting a phase error of two periodic signals, which is characterized by 13. An analog-digital conversion means for digitizing each of two signals having a same cycle and having a phase difference, and a digital signal processing means for correcting a phase of the two signals having the same cycle, The digital signal processing means is any one of claims 1 to 12.
2. A phase error correction device for two periodic signals, wherein the phase is corrected by the method described in any one of 1. 14. The phase error correction apparatus for two periodic signals according to claim 13, further comprising a storage unit that does not lose a stored value regardless of whether the power is on or off, and the digital signal processing unit stores the correction coefficient in the apparatus. In addition, the phase error correction device for two periodic signals is characterized in that when the power is turned on, correction is performed using the previous correction value.